The invention relates to an arrangement for converting an original picture signal representing a sequence of frames, each of which is composed of two interlaced fields, into a converted picture signal which has a double field frequency with respect to the original picture signal.
When converting a picture signal into such a converted picture signal which, with respect to the original picture signal, has a double field frequency, there is the problem that every second field of the converted picture signal must be newly generated, because no corresponding field of the original picture signal is available with respect to time and also with respect to the picture information.
In simple arrangements for doubling the field frequency, every field is doubled. A moving object in the fields of the converted picture signal is imaged twice in the same position before it jumps to the next position in the two subsequent fields. Since the human eye cannot follow these jumps, it is incident on the average speed of motion and observes a moving object from field to field at different positions. This leads to a double structure and motion blurr.
In other arrangements for field doubling of a picture signal a motion compensation is therefore provided by means of which the motion between two fields of the original picture signal is determined so that the motion can be taken into account in fields of the converted picture signal to be generated therebetween as a function of time and a corresponding interpolation can be performed. However, such arrangements have the further problem that possibly present noise is also to be reduced and that the line flicker, which still occurs in spite of the doubling of the field frequency in picture signals generated by way of interlaced scanning, is to be reduced. In the state of the art arrangements are only known in which a motion compensation is combined either with a noise reduction or with a line flicker reduction.